This invention relates to internal water drainage of a hollow member structural assembly in a railroad pressure discharge hopper car or the like, including a method for drainage of the hollow member structural assembly after hydrostatic testing of the railroad car.
Powdered, bulk commodities (i.e., flour, starch and talc) as oftentimes transported in pressure differential covered hopper cars. These cars are constructed to accommodate a predetermined internal pressure in order to allow pressure discharge unloading of the bulk commodity from within the railroad car. Fast and efficient unloading of the commodity to remote receiving bins of a customer is thus possible. For example, unloading rates of up to 100,000 pounds per hour may be achieved where the internal pressure of the car is operated at about 14.5 psi. This means that the hopper car must accommodate that amount of internal pressure (with an adequate safety factor) during unloading without causing damage to any of the structural components of the car.
In order to verify the structural integrity of each such pressure discharge rail car manufactured, each such car is subjected a predetermined internal pressure. For such testing, hydrostatic pressure testing is used, following construction of the car. This method requires the hopper car to be filled with water and then to be pressurized to a predetermined pressure in order to verify the structural integrity of the railroad hopper car and its structural components.
In some cases, such pressure discharge hopper cars are provided with a number of adjacent hoppers or compartments which are separated by compartment partition walls or bulkheads. These partition walls or bulkheads terminate short of the top or upper end of the hopper car in order to permit the powdered bulk commodities to fill up each compartment and then flow into an adjacent compartment through large openings between the top of the compartment walls or bulkheads and the top of the hopper car. Typically, interconnected hollow structural members are provided for internally supporting and reinforcing the compartment walls or the bulkheads relative to the elongated shell which forms the hopper car.
Since these hollow structural members may not be airtight during pressure testing of the car, these hollow structural members oftentimes become filled with water during the hydrostatic pressure testing of the hopper car. While the water used in hydrostatic testing each of the railcars manufactured can be easily removed through bottom outlets associated with each compartment or hopper, it has been found that some residual water remains trapped in the interconnected hollow structural members. Unfortunately, this results in water deterioration and corrosion of the internal surfaces along the compartment walls or bulkheads and other internal surfaces within the compartments or hoppers. Also over time, this entrapped water, often having a high concentration of rust, seeps out of the hollow members and discolors the interior of the car and the lining and may partially contaminate a lading. Because customers demand purity in the powdered bulk commodities, any rust from the inside of the compartments, caused by water deterioration, can create substantial problems. Therefore, when residual water remains inside the interconnected hollow structural members and causes damage to inside surfaces of the hopper car, it is necessary to rework such surfaces and remove all corrosion and other debris. This often means that the lining for the car must be repaired. As can be appreciated, this is not only costly, but is a time consuming process requiring inspection and subsequent repair of any deteriorated surfaces in the hopper car.